1. Field of the Invention
This invention relates to rotary brushes for cleaning, polishing, scrubbing, and the like, whose working surface is a flat or disk shape. The working surface is formed from a plurality of bristles, that is, separate, usually artificial elements, arranged in near parallel relation such that their assembled ends constitute collectively the working surface. The invention particularly relates to such a brush having particular utility in municipal and industrial powered rotary operations.
2. Description of the Prior Art
In rotary driven brushes adapted for heavy industrial and municipal use, holders for the brush bristle material have typically been cast with a plurality of pairs of bristle-receiving passages extending through the holder from the top to the bottom. After the holder was cast, bites or tufts of U-shaped bristles were disposed in each pair of bristle-receiving passages to extend through the holder out to a working face. Examples of such holders are to be found in U.S. Pat. Nos. 3,526,919; 3,678,530 and 3,875,607. Rotary brushes of this construction suffer the distinct disadvantage of requiring considerable labor to ensure proper insertion of the bristle material into the holder after the holder was cast.
In some molded rotary brushes of this type, the apertures receiving the bristles did not extend all the way though the holder or brush back, but rather extended only part way through, as sockets to receive the brush bristle together with typically a staple holding the bristle tuft in place. Examples of brushes of this construction can be found in U.S. Pat. Nos. 2,539,211 and 3,310,827. Brushes of this configuration still required the time-consuming positioning and securing of the individual tufts in the sockets of the holder. Further, since in both of these configurations the brush bristle material is added after the brush back or holder is formed, it is easy for the bristle material to work free under the continuous buffeting and flexing experienced during operation of the brush.
In order to reduce the amount of time and effort expended in positioning the tufts of bristles into the appropriate apertures of a brush back or holder, attempts have been made to mold a body of plastic resin around the bristles, thereby securing the bristles once the molded body of resin is cured. While such a procedure has met with success in some instances, under the severe, heavy work experienced by heavy-duty rotary powered industrial and municipal brushes, the bristles repeatedly work themselves free from the molded body of resin. In order to overcome this difficulty, some brushes of this type have been made wherein the molded body of resin extends over a major portion of the bristle length and may extend all the way to the brush face. This severely restricts the bristle action desired for the proper cleaning, polishing and scrubbing action of the brush bristles. An example of a brush of this type is to be found in U.S. Pat. No. 3,404,422.